Structures and functions of gicerin, a novel cell adhesion molecule.

我们报道了诱导鸡睫状神经突起生长的神经突起生长因子(NOF)，揭示了它是一种属于层粘连蛋白家族的细胞外基质蛋白。另一方面，我们已经分离到作为NOF受体的gicerin，这是一种属于免疫球蛋白超家族的细胞黏附分子。Gicerin显示出同嗜性和异嗜性两种细胞黏附活性。Gicerin有两个异构体(S-和L-)，它们的胞质结构域长度不同。Gicerin仅在发育神经系统的突触发生和细胞运动过程中表达，此后迅速下降。我们还发现Gicerin参与了肾小管和支气管的小管形成。Gicerin在嗅球和C6胶质瘤细胞中也有表达。结果发现，舌下神经切断后7-14天，损伤神经元和反应性星形胶质细胞中Gicerin的表达无明显变化。提示Gicerin参与了反应性星形胶质细胞网络的形成和神经末梢突起的生长。

We have reported the neurite outgrowth factor (NOF) that induces the neurite outgrowth from chicken ciliary neurons and revealed that it is an extracellular matrix protein which belongs to laminin family. On the other hand, we have isolated gicerin as a NOF receptor, which is a cell adhesion molecule belonging to a immunoglobulin superfamily. Gicerin exhibits both homophilic and heterophilic cell adhesion activities. Gicerin has two isomers (S-and L-) which differ in the length of cytoplasmic domain. Gicerin is expressed only during synaptogenesis and cell movement in development nervous system and thereafter rapidly is decreased. We also found that gicerin is involved in the tubular formation in the renal tubules and bronchus. Gicerin is also expressed in the olfactory bulb and C6 glioma cells. We found that gicerin expression was unregulated in the the injured neurons and reactive astrocytes at 7-14 days after the transection of the hypoglossal nerve. It is suggested that gicerin is involved in the network formation of reactive astrocytes and also the neurite outgrowth from the transected nerve end.